The incorporation of the Catalan Counties into the Aragonese Kingdom meant that the newly expanded kingdom was linguistically heterogeneous, with Catalan spoken in the eastern region, and Aragonese in the west. When the Aragonese reached the southern region of Murcia, the Aragonese had no peoples to repopulate with. The territory was ceded to the Kingdom of Castile and so, the Aragonese language started its recession.
The spread of Castilian, now known as Spanish, as the common language in the peninsula, together with the protective effect from it that Aragonese played for the Catalan language, meant that further recession was to follow. One of the key moments in the history of Aragonese was when a king of Castilian origin was appointed in the 14th century.
The annexion of Aragon by Castile and the progressive suspension of all capacity of self-rule from the 16th century meant that Aragonese, while still widely spoken, was limited to a rural and colloquial use, as the nobility chose Spanish as their symbol of power. The suppression of Aragonese reached its most dramatic point during the rule of the dictator Francisco Franco in the 20th century. Pupils were beaten in schools for using it, and legislation forbade the teaching of any language that was not Spanish.
The constitutional democracy voted by the people in 1978 meant an increase in the literary works and studies conducted in and about the Aragonese language. However, it may be too late for this language. Nowadays, Aragonese is still spoken natively within its core area, the Aragonese mountain ranges of the Pyrenees, and learnt as a second language by other inhabitants of the country in areas like Uesca, Zaragoza, Exea, and Teruel. According to recent polls, all together they only account to around 30,000 speakers, making this language one of the closest to extinction in Europe.